This Greasemonkey script adds options to StackOverflow to 

 1. expand answer box
 2. expand code box
 3. resize code font size 
 4. widen the entire page
 5. remove sidebar 

Source: https://github.com/yodog/userscripts/blob/master/stackoverflow_code_box_options.user.js

Limited <s>(for now)</s> to Firefox 52 ESR  
Still <s>working on</s> wondering if I'll be upgrading to webextensions  
Probably not

[![so-menu][1]][1]
[![so-wide-screen][2]][2]


  [1]: https://i.sstatic.net/hBW90.png
  [2]: https://i.sstatic.net/ep95e.png